Background

In accordance with 10 U.S.C §115(a), Congress sets the maximum size (i.e., end-strength) of the active and reserve components of the Armed Forces annually, typically in a National Defense Authorization Act (NDAA). Congress also appropriates funds for the pay and benefits of these personnel.

End-strength specifically refers to the actual number of personnel in a branch on the last day of the fiscal year (i.e., September 30). The enacted end-strength figures for an FY2027 NDAA would be for September 30, 2027. Congress also periodically sets minimum end-strength levels for the Armed Forces, which may be lower than or equal to the maximum authorized level. While Congress authorizes minimum and maximum end-strengths, each military service manages its force through recruiting and retention efforts to achieve an actual end-strength.

Typically, actual end-strength falls within the congressionally authorized minimum and maximum end-strengths. However, there are circumstances in which the actual end-strength may fall outside the authorized range. For example, under 10 U.S.C. §115(f)(3), the Secretary of Defense (who is using "Secretary of War" as a "secondary title" under Executive Order 14347 dated September 5, 2025) may—after determining "such action is in the national interest"—vary the end-strength of any of the services by no more than 3%. Recruiting and retention shortfalls may cause one or more of the services to fall below their minimum authorized strength.

Per 10 U.S.C. §10102, the reserve component provides "trained units and qualified persons available for active duty in the armed forces, in time of war or national emergency, and at such other times as the national security may require, to fill the needs of the armed forces whenever more units and persons are needed than are in the regular components."

In accordance with 10 U.S.C. §113a(b)(2), the Secretary of Defense is required to submit end-strength requests for the reserve component in an annual budget request to Congress. Congress is not bound by these requests but considers them while deliberating end-strength levels. From FY2001 to FY2026, Congress authorized end-strengths similar to the Pentagon's requested numbers.

The reserve component consists of the federal reserve forces of the Army, Navy, Air Force, Marine Corps, and Coast Guard, as well as the Army National Guard and Air National Guard. The Space Force does not have a reserve component. It is a single-component armed service with personnel serving in an inactive or active-duty status (10 U.S.C. §20001). Either component of the National Guard may be mobilized under federal or state authority and perform homeland security missions that may include responding to civil unrest and natural disasters and guarding domestic airspace.

End-Strength Trends, FY2001-FY2027

Congress has varied authorized end-strengths over time in response to factors such as national security priorities, budget constraints, and recruitment challenges (see Figure 1). In the report (S.Rept. 118-58) accompanying the Senate-passed FY2024 NDAA (S. 2226 §411), the committee stated that it chose to recommend lower end-strengths than requested for the Selected Reserve (i.e. the portion of the Reserve Component that trains regularly and is frequently mobilized) because "legislating unreachable end strength numbers would set the military services up for failure" by "encouraging quantity over quality in recruiting." It remains unclear whether incremental reductions in previous years may have stemmed in part from this concern.

In other instances, Congress increased authorized end-strengths. For instance, in the FY2017 NDAA (S. 2943), Congress authorized an Army National Guard end-strength that was 8,000 personnel greater than the number requested by the Defense Department.

Figure 1

. End-Strength Trends, FY2001-FY2027

Figure is interactive in HTML report version.

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Source: CRS analysis of Congress.gov for FY2001-FY2026 data. FY2027 data are from the President's budget request.

Notes: FY2001-FY2026 data comprise authorized end-strengths from National Defense Authorization Acts. Coast Guard Reserve, part of the Department of Homeland Security, is not shown.

FY2027 NDAA

The House-passed (H.R. 8800) and Senate committee-reported (S. 4784) versions of an FY2027 NDAA contain end-strength figures identical to those requested by the executive branch (see Table 1).

Table 1. FY2026 and FY2027 Reserve Component End-Strengths

Service	FY2026 Enacted End-Strength	President's Budget Request	H.R. 8800	S. 4784	Change from Enacted FY2026 to FY2027 Request
Army National Guard	328,000	331,300	331,300	331,300	+3,300
Army Reserve	172,000	172,000	172,000	172,000	+0
Navy Reserve	57,500	56,500	56,500	56,500	-1,000
Marine Corps Reserve	33,600	34,700	34,700	34,700	+1,100
Air National Guard	106,300	107,400	107,400	107,400	+1,100
Air Force Reserve	67,500	67,400	67,400	67,400	-100
Total	764,900	769,300	769,300	769,300	+4,400

Source: Congress.gov; Department of Defense, Office of the Under Secretary of Defense (Comptroller).

Notes: Coast Guard Reserve, part of the Department of Homeland Security, is not shown.

Potential Issues for Congress

Consideration of the FY2027 NDAA may include discussions on reserve component end-strength. Related issues Congress may debate may include the following:

Do the reserve forces possess sufficient end-strength to fulfill all mission requirements—including domestic security and disaster relief activities?
How might U.S. security objectives in the Western Hemisphere or the Middle East require adjustments to reserve component end-strengths?
What is the role of the reserve components in service-level restructuring projects (such as the Marine Corps Force Design Initiative, the Army Transformation Initiative, or the Navy's "Golden Fleet")?
To what extent are these requests informed by the services' recruitment and retention plans?
How might the reserve forces request affect the active component-reserve component force mix and the Armed Forces' capacity to meet current defense objectives?
Should requested funding levels be met or adjusted?